Quartzite Pebble

Physical Properties

Hardness: 7 on Mohs scale. Color: Off-white to yellowish tan. Luster: Vitreous to dull. Structure: Granular/crystalline. Cleavage: Indistinct. Specific Gravity: 2.6 - 2.8.

Formation & Geological History

Formed from quartz-rich sandstone subjected to extreme heat and pressure (metamorphism). The rounded shape indicates secondary transport and erosion by water (fluvial or beach action).

Uses & Applications

Construction aggregate, decorative landscaping, and high-purity silica for pharmaceutical and industrial glass manufacturing.

Geological Facts

Quartzite is so tough that it often outlasts the surrounding rock in weathering events, forming ridges or hills known as 'quartzite monoclines.' It is harder than a steel knife and will easily scratch glass.

Field Identification & Locations

Identify in the field by its grainy texture and exceptional hardness; it won't fizz with acid like limestone and cannot be scratched by a steel blade. Common in ancient riverbeds and glacial deposits.

Identified on: 4/26/2026

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